Low C/N_0 Carrier Tracking Loop Based on Optimal Estimation Algorithm in GPS Software Receivers

作     者：Miao Jianfeng Chen Wu Sun Yongrong Liu Jianye 

作者机构：Navigation Research Center College of Automation Engineering Nanjing University of Aeronautics and AstronauticsNanjing 210016 China Department of Land Surveying and Geo-informatics Hong Kong Polytechnic UniversityHong Kong China 

出 版 物：《Chinese Journal of Aeronautics》 (中国航空学报（英文版）)

年 卷 期：2010年第23卷第1期

页      面：109-116页

核心收录：

学科分类：080904[工学-电磁场与微波技术] 081802[工学-地球探测与信息技术] 0809[工学-电子科学与技术（可授工学、理学学位）] 08[工学] 0810[工学-信息与通信工程] 081105[工学-导航、制导与控制] 0818[工学-地质资源与地质工程] 080402[工学-测试计量技术及仪器] 0804[工学-仪器科学与技术] 0802[工学-机械工程] 081001[工学-通信与信息系统] 0825[工学-航空宇航科学与技术] 0811[工学-控制科学与工程] 0801[工学-力学（可授工学、理学学位）] 

基　　金：National Natural Science Foundation of China(40671155) National High-tech Research and Development Programof China(2006AA12A108) Research Program of Hong Kong Polytech-nic University(G-U203) 

主　　题：global positioning system signal processing Kalman filters software radio phase locked loop 

摘      要：Suppressing jitter noises in a phase locked loop（ PLL） is of great importance in order to keep precise and continuous track of global positioning system （GPS）signals characterized by low carrier-to-noise ratio（ C/No ）. This article proposes and analyzes an improved Kalman-filter-based PLL to process weak carrier signals in GPS software receivers. After reviewing the optimal-bandwidth-based traditional second-order PLL, a Kalman-filter-based estimation algorithm is implemented for the new PLL by decorrelating the model error noises and the measurement noises. Finally,the efficiency of this new Kalman-filter-based PLL is verified by experimental data. Compared to the traditional second-order PLL, this new PLL is in position to make correct estimation of the carrier phase differences and Doppler shifts with less overshoots and noise disturbances and keeps an effective check on the disturbances out of jitter noises in PLL. The results show that during processing normal signals,this improved PLL reduces the standard deviation from 0. 010 69 cycle to 0. 007 63 cycle, and for weak signal processing,the phase jitter range and the Doppler shifts can be controlled within ± 17° and ±5 Hz as against ±25° and ＋ 15 Hz by the traditional PLL.